Am I using the right t-test for each comparison?

Briefly, I have 2 groups: healthy control & patients (n=9 in each group). Blood collected from each of this group before and after certain treatment. Then I went on to compare RNA expression, cell counts, etc between these groups, as well as before-after comparison. Controls are sex-matched.

----> for these two cell counts analysis (3 & 4) I used normal unpaired t-test (therefore, comparing the means).

5) cell counts comparing before & after treatment in each group (e.g. patients before vs. patients after)

----> this one I used normal paired t-test. However I'm not sure if I should use Wilcoxon instead. Is it possible for one group is normally distributed, while the other is not? If this is true, which test should I use?

6) Is there any other statistical test I can derive from the data I have? I'm asking this because my controls are sex-matched to the patients but the matched test I did was only on the individual group (before-after), not comparing both groups..if you get what I mean...

Can anyone here help me to validate the statistical test I used in the above situations?

I've been asking around and reading loads about t-test, but it seems the more I read the more I get confused . I'm afraid if I've been doing the wrong statistical analysis all this, it'd be a huge waste of time.